Ordinarily, as fuels in combustion appliances, such as lighters for smoker's requisites, other types of lighters, torches, and illumination devices, alcohol fuels, such as ethyl alcohol, petroleum benzine types of benzine fuels, or liquefied gas fuels, such as butane gas or propane gas, have heretofore been utilized.
The performances, the levels of convenience of handling, and the design structures of the combustion appliances vary in accordance with the kinds of the fuels used, and the fuels have their own features. For example, in cases where the liquefied gas fuels are used as the liquid fuels, since the liquefied gas fuels have a high gas pressure at temperatures falling within the range, in which the combustion appliance is used, the vessel for storing the fuels must have a pressure-resistant structure. Also, the flame length varies in accordance with variations in gas pressure. In particular, the liquefied gas fuels have the characteristics such that their gas pressures markedly vary logarithmically with respect to temperatures, and therefore the problems occur in that the flame length changes markedly, depending upon temperatures. In order for the change in flame length to be reduced, a special design countermeasure for carrying out temperature compensation for a fuel feeding mechanism of the combustion appliance must be taken. Therefore, the structure cannot be kept simple, and the cost cannot be kept low.
As for the liquid fuels, such as the alcohol fuels, they are liquids at normal temperatures and have comparatively low vapor pressures. Therefore, the fuel storing section need not have a pressure-resistant structure. Accordingly, the structure of the combustion appliance can be kept simple, and the cost can be kept comparatively low. In the combustion appliances for the liquid fuels, ordinarily, as means for feeding the liquid fuel from the fuel storing section to the burning section, a combustion wick, which sucks up the liquid fuel with the capillarity through open pores or through minute spaces formed between thin fibers in a fiber bundle and by the utilization of the surface tension of liquid fuel and allows the liquid fuel to burn at a top end portion of the wick, has heretofore been used. Specifically, in the combustion wick, the liquid fuel is sucked up by the utilization of a string-like wick formed by twisting fibers, a bundle of glass fibers, a wick formed by bundling glass fibers with cotton threads and interweaving thin metal wires for preventing the bundle from becoming loose, or the like. The lower end portion of the combustion wick has the functions for sucking up the liquid fuel, and the sucked-up fuel is burned at the top end portion of the wick.
Gas lighters utilizing a liquefied gas as the fuel, which are provided with mechanisms designed such that the fire may be extinguished automatically after a predetermined amount of fuel has been burned, have been proposed in, for example, Japanese Unexamined Patent Publication Nos. 7(1995)-190356, 7(1995)-158852, and 8(1996)-219456. The automatic fire extinguishing functions are constituted for various purposes. The mechanisms are designed such that a valve body may be operated in association with a lighting operation and the fuel gas fed from a fuel tank may be measured and burned.
However, with the mechanisms for burning a predetermined amount of fuel in the aforesaid gas lighters utilizing a liquefied gas, since the liquefied gas utilized as the fuel is stored in a high-pressure state in the fuel tank, it is difficult to measure a predetermined amount of fuel. Due to the difficulty in measuring a predetermined amount of fuel and the aforesaid fluctuation in gas pressure with respect to temperatures, a large variation in combustion time occurs. Also, the problems occur in that a valve mechanism having a complicated structure must be used and the cost cannot be kept low.
Accordingly, the object of the present invention is to provide a combustion appliance for a liquid fuel, which has functions for carrying out combustion of a predetermined amount of fuel, i.e. the combustion for a predetermined length of time, and thereafter extinguishing the fire.
One of applications, in which it is desired that the combustion flame be extinguished after the combustion has been carried out for a predetermined length of time, is a lighter for smoker's requisites wherein, after a tobacco has been lighted, the combustion flame which is not necessary any more is to be extinguished. In such cases, for the lighting of the tobacco, it is sufficient for the combustion for several seconds to be carried out. When a tobacco lighting failure is taken into consideration, it is sufficient for the fuel to burn for 10 seconds or at most 20 seconds. Longer combustion time results in waste of the fuel and partial overheating and damage of constituent parts of the lighter. In order for such problems to be eliminated, the fire should preferably be extinguished after the combustion has been carried out for a predetermined length of time.
As described above, examples of the combustion appliances for a liquid fuel, which are provided with a combustion wick for sucking up a liquid fuel and burning it, include lighters for smoker's requisites, other types of lighters, and various types of illumination devices. ordinarily, such combustion appliances for a liquid fuel are provided with a mechanism for extinguishing the combustion flame by carrying out a particular fire extinguishing operation after the lighting. However, from the view point of operability, it is often desired that the fire goes out automatically after the combustion having been begun by the lighting operation has continued for a predetermined length of time. Also, in the cases of several combustion appliances, it may be desired that the fire goes out after a fire extinguishing operation has been carried out and the combustion has then been continued for a predetermined length of time. Further, in other combustion appliances, it may be desired that the continuous combustion is continued for a length of time having been set with a timer and thereafter the fire is extinguished automatically by the operation of the timer.